BIOLOGIYA MORYA, 2016, Vol. 42, No. 3, pp. 189-194

Distribution of zooplankton and bowhead whales, Balaena mysticetus Linnaeus, 1758, in Akademiya Bay, Sea of Okhotsk

© 2016 V. V. Melnikov, Yu. V. Fedorets

V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, Vladivostok 690031

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The modern pattern of distribution and feeding habits of the bowhead whale, Balaena mysticetus, in the Sea of Okhotsk are studied. The existence of a feeding aggregation of this whale species in the southwesternmost portion (apex) of Ulban Bay has been confirmed. The animals feed in shallow waters with depths of 3-5 m, which are only slightly larger than their body height. The quantitative composition and species structure of zooplankton at the stations set near feeding whales have been analyzed. In the samples taken in the immediate proximity to the feeding whales, the abundance of zooplankton reached 31 409 ind./m³ with the average value of 17 565 ind./m³. The lowest abundance, from 56 to 1879 ind./m³ (mean 927 ind./m³), was in the samples from western Konstantin Bay, where bowhead whales were not observed. In 16 samples collected in the immediate proximity to the feeding whales in the shallow waters of Ulban Bay, the average zooplankton biomass was 547.9 mg/m³, being 3.9 times as high as that in the samples from waters where the whales were absent. Copepods dominated quantitatively at all the stations in Akademiya Bay. The proportion of euphausiids in the zooplankton biomass was smaller than 1%, both near the feeding whales and in the absence of whales.

Key words: Sea of Okhotsk, Akademiya Bay, bowhead whale, zooplankton.